Performance of numerical schemes in the simulation of two-phase free flows and wall bounded mini channel flows

Abstract

In the present paper, simulations of two-phase flows using volume of fluid method are presented and analyzed. Two important problems in two-phase flow simulations are identified—dependence of the simulation on momentum discretization scheme and on the gradient calculation scheme. The dependence of the solution on the momentum discretization schemes is analyzed using bubble rise simulations, which does not involve the wall adhesion (contact angle), and compared with published results. Performance of the momentum discretization schemes with the inclusion of wall adhesion effect is analyzed using simulations in T-junctions of minichannels and validated against experimental results available in literature. Reasoning for the better performance of a few schemes over the others is provided. Sensitivity of the solution to the gradient calculation method is analyzed using T-junction simulations and flow maps are generated with different gradient calculation schemes. These flow maps are compared with experimental flow maps reported in literature and the gradient calculation scheme that generates a physically realizable flow map is reported. Unlike most of the work to date, which only explore small parts of the flow map containing a single regime, we study the capability of the commercial software FLUENT in simulating across several flow regimes observed in experiments.